Figure 11.

Functionalization of nanobodies by using the lipoic acid ligase (LpIA). a) LpIA recognizes the 13 amino acid LAP tag (green) and ligates an aldehyde‐containing lipoic acid derivative to the side chain of a lysine residue. A subsequent oxime‐forming reaction enables site‐specific functionalization of the nanobody. b) A nanobody‐based activation immunotherapeutic is shown. An anti‐HER2 nanobody was site‐specifically functionalized with a dinitrophenyl (DNP) moiety using LpIA. The DNP acts as an endogenous antibody‐recruiting domain, facilitating a targeted immune response upon HER2 binding of the nanobody. The nanobody is depicted in gray, the introduced functionality in red. The crystal structure of a GFP‐binding nanobody is used in (a) and (b) [PDB ID: 3G9A].17